Levosimendan (marketed as Simdax) is an inodilator-a medication that both increases heart muscle contractility (inotropy) and dilates blood vessels (vasodilation).
It is primarily used for the short-term treatment of acutely decompensated severe chronic heart failure when conventional therapy is insufficient.
Levosimendan operates through three primary pharmacological pathways: Calcium Sensitization: It binds to cardiac troponin C in a calcium-dependent manner, increasing the heart’s contractile force without raising intracellular calcium levels or significantly increasing oxygen demand.
Vasodilation: It opens adenosine triphosphate (ATP)-sensitive potassium channels in vascular smooth muscle, leading to systemic and coronary vasodilation: reducing both preload and afterload on the heart.
Cardioprotection: By opening mitochondrial potassium-ATP channels, it may provide cardioprotective, antioxidant, and anti-inflammatory effects.
Clinical Applications: Acute Heart Failure: Indicated for patients with low cardiac output and high filling pressures.
Cardiac Surgery: Used to manage low cardiac output syndrome following cardiac procedures, with meta-analyses suggesting benefits in mortality and renal protection for high-risk patients.
Critical Care: Investigated for use in septic shock, right ventricular failure, and cardiogenic shock.
Administration: It is typically delivered as a 24-hour intravenous infusion.
A loading dose may be used if rapid action is needed, but it is often avoided in patients with low blood pressure (systolic <90 mmHg) to prevent severe hypotension.
Side Effects: Common adverse events include headache, hypotension (low blood pressure), atrial fibrillation, and hypokalemia.
It is not approved by the FDA for use in the United States as of early 2026.
Its effects are not attenuated by the concurrent use of beta-blockers.